Microwave when trying to microwave sparks and smoke starts. I notesed the cover on right side when looking in microwave has hole burned through it what do I need to do.

save your sanity and get another one at a resale shop..that one may catch fire..

If your positive it is not arcing behind the waveguide cover I would think it has to be in the control area. You will have to turn off power to the unit and remove the control panel and look to see if you can find any burn marks or soot, to indicate where your problem may be. I have found burnt connectors at the relays or even possibly burnt wires to the door switches. Careful! the capacitor on these can hold a charge for a long time and can shock you pretty good. Only work on something like this with the power to it off and the capacitor discharged. Microwaves do not come through the little round holes those are typically an RF screen to prevent microwaves from getting through. A lot of times that is where the cavity lamp shines through.

it may be repairable but not by yourself
take it in for a quote and proper diagnosis

Presuming that you have iliminated the possibility of any metal objects that are not meant to be in the machine being in there (and this includes dishes and other items with silver or gold leaf on them, which WILL spark and burn!) then take a look inside the oven its self. You will find a waveguide cover. It is usually a strange flakey silvery plastic/card like material called Mica and is usually on the same side of the microwave wall as the control panel (So if the picture on this thread is accurate, I will guess the Mica cover is on the right hand wall inside as you look at the machine from the front) . Over time, the magnatron (the thing that creates the microwave energy) will often burn a hole through the mika, or cause a dark brown or black burn mark in it. If this cover is even slightly damaged then it may well cause sparking inside the machine. These covers are designed to be removed and you can buy replacements for them from electrical stores.

I had the same problem with my microwave. There is a cover on the inside of the microwave called a "wave guide cover" which can cause the symptoms you described. It can be caused by grease or debris accumulating around or on the cover. Mine actually began to smoke and appeared burned in the top corner. It is very easy to remove and replace, and is pretty inexpensive and can probably be purchased online. They are model specific, so be sure to purchase the correct one for your unit.

Arcing is often the result of the cover over the magnatron (The thing that produces the microwaves) being aged, burned or damaged. If you look inside the oven, you will see a cover (usually square or round and around 3-5 inches across depending on the machine)made from a flakey silver plastic/fibre material. If this is burned or has a hole, it needs replacing and this will probably cure your problem.

the burning is normally caused by a small particle of food getting stuck on the waveguide cover, this then carbonises and starts to arc. replacing cover should return oven to normal

The Magnetron has failed, causing the waveguide to become damaged. If the waveguide is damaged/burned the microwave can not be repaired and should be replaced.

Proberly wave guide cover at side it can get grease behind it,And when you used it with small load it tried to cook it and then burned the mica cover,Take mica cover off and try it without it to seeif problem resolved if ok,New cover can be obtained if req.Regards grandadfixer

my guess would be the wave cover. sometimes they smoke and makes sparking sounds. does it still heat food?...if it does, then its not the magnetron.